In terms of the item itself, they are one of the best tier 5 boots for a caster.
I received this pattern yesterday and was immediately able to make the boots. Presumably any 375 tailor in a 25 man instance will already have or be able to obtain Primal Nethers, and the Shadowcloth and Spellcloth take about a week of transmutes and trading to obtain. The item itself is also bind on pickup, and combined with the relative ease of getting the materials, the recipient of the pattern is essentially getting an item, as opposed to a pattern to make money from. Comment by 23639The Bind on Pickup pattern randomly drops off mobs in Serpentshrine Cavern and The Eye - 25 man raids.